Two-cycle engine.



K. E. DUNBAR.

TWO-CYCLE ENGINE.

APPLICATION FILED JAN. 27, 1912 Patented Jan. 5 1915.

2 SHEETSSHEET l.

K.E. DUNBAR. TWO-CYCLE ENGINE. APPLICATION-FILED JAN. 27, 1912. .11., 13 6 1 a 2 8HEETSBHEET 2.

Patented Jan. 5, 1915.

L MNM .M M WNI lit) KARL E. DUNBAB, 0F PITTSBURGH, EEN'NSYLVANIA.

Two-crate ENGINE.

31,123.,d6il.

T 0 all whom it may concern .1

Be it known that I, KARL E. DUNBAR, a citizen of the United States,residing at No. 6732 Frankstown avenue, in the city of Pittsburgh, inthe county of Allegheny and State of Pennsylvania, have invented a newand useful Improvement in Two Cycle Fmgines. set forth in the annexedspecification.

The object and nature of my said inven tion is the furnishing andproviding ot a simple economic and practicable two-cycle engine ormotor, that will create or generate power or force by means of thecompression and explosion of ordinary operating "gases, liquids orexplosives, by the compression and explosion of any or all of the saidgases, vapors or explosives, in. the same power unit, in a morepractical, simple, advantageous and economic manner, than by crank caseor any other manner of compression now known or used for such purposes.

Figure l of the drawing shows a vertical sectional view of theconstruction of an engine or motor using my invention, at the end of theexplosion or power stroke. Fig. 2- of my said drawing shows a side viewof the piston together with the gas conveyer attached. Fig. 3 of saiddrawing shows a plan view of the piston looking up or toward the pistonhead. F ig. 4 is a crosssectional view on the line -'l4, Fig. 1. Fig. .3of my said drawing shows a vertical sectional view of the constructionof an engine or motor using my invention, at the end of the upward orbackward stroke of the piston. Fig. 6 is a partial cross sectional viewof the cylinder showing the top of the gas conveyer closed. Figs. 7 and8 are detail views of the same. Fig. 9 shows a modification eliminatingthe traveling gas conveyer.

My invention comprises a motor or engine with cylinders of threedifferent diameters, asshown in Figs. 1. r and 5. Beginning at the topof the verticalsectional view in Fig. 1, with the small cylinder E namedthe power or explosion chamber, the next or larg est cylinder V whichforms the outer boundary of the compression chamber. designated by theletter B shown in Fig. 5; and ending with the cvlinder of the seconddiameter marked T in Figs. 1 and 5. The cvlinder T is cast or madeseparate from the cylinders ll and V in order to admit the piston H-K-T.The cylinder Specification br Letters Tatent.

Patented Jan. 5., lwilfi.

Application filed January 27, ram. serial in. 73,929.

V is cast or made with the flange X. The cylinder T has the flange U andthese two flanges X and U are bolted or fastened together in a suitablemanner, thus connecting the three cylinders as shown in Figs. 1 and 5.Or these cylinders may be fastened together in another manner, insteadof the large cylinder V and second cylinder T being bolted together asshown at the flanges U and X, the flange X may be made on the bottom ofthe explosion cylinder E, and the flange U on the top edge of thecylinder V Just simply a different place to fasten the machine together,or the cylinders may all be cast or made separately and fastenedtogether in a suitable manner. The purposes of each cylinder may beexplained in the same order as above: first, the top or small cylinderFE. Figs. 1 and 5,is the chamber into which the compressed gases orvapors are admitted and exploded to create or generate the power orforce which drives the engine or motor; the second or largest cylinderV, Figs. 1 and 5 forms the outer boundary of the chamber where the gasesor vapors are drawn in and primarily compressed; the third, and 5, whichis second in diameter is used to keep the expanding rings R in thecompression sleeve T from springing out of place. and is the cylinder inwhich the compressibn sleeve 1 operates and prevents the compressedgases or vapors from escaping in that direction. There is also a pistoncomposed of three sections, the diameters of which correspond with thediameters of the three cylinders before mentioned, in which each one ofthese sections of the piston must respectively fit and operate. Thesesections may be made or cast all in one piece or made or cast separatelyand fastened together in a suitable manner. Commencing with the smallestsection of the piston, called the piston head, H, Figs. 1, 2, 3 and 5,which works in the power or explosion chamber Ez next in order is thelargest section K, Figs. 1, 2, 3, and 5, which I have named thecompression ring, this compression ring K works in the largest cylinderV, Figs. 1 and 5. The third section I which I call. the compressionsleeve, is second in diameter and fits into and works in the cylinder T,Figs. 1 and 5.

or cylinder T, Figs. 1

The compression chamber, lettered B in Fig. 5, is a circular orring-like chamber formed by the cylinder V, the compression ring K, thecompression sleeve 1 and the flange U.

The compression sleeve I is used to form the inner wall of thecompression chamber B, Fig. 5, and thus prevent the escape of compressedgases or vapors in that direction, also to overcome loss of suctionwhile the vaporized gases or liquids are being drawn or sucked into thecompression chamber B through the port A, by the compression ring Kreceding and acting as a pump when the piston ascends or makes thebackward stroke. hen the piston HKI ascends or recedes, as a unit as itmust do. being cast or made in one piece, or fastened together in asuitable manner, a. suction is created in the compression chamber B;this chamber l3 constantly increasing in volume as the compression ringK recedes or ascends in the compression cylinder V, until the end of thebackward or upward stroke is completed (Fig. 5) by the suction therebyformed the vaporized or aerated liquids are sucked in from thecarburetor, if one is used, or from whatever other means is used, past asuitable valve or cut oil AA through the port A (Fig. 5), this valve orcut off AA being open while a proper charge of the vaporized or aeratedliquid is beingdrawn or sucked into the compression chamberfB, andclosed while the compression is being made, and until the compressionchamber B is ready to draw in the next charge of the gas or liquid. Thisvalve'AA may be located at the port A or at any proper distance from theport A. The valve or cut off may be of any suitable design.

\Vhen the compression ring K has reached the end of the upward orbackward stroke it begins to descend or go forward, and an explosion ofthe compressed gases or vapors from the preceding charge occurs in thepower or explosion chamber E abo e described, and the compression ring Kis thus forced downward or forward on the power stroke thereby primarilycompressing the charge previousl drawn into the compression chamber 3;as the compression ring K descends the compression chamber B becomessmaller thereby compressinfl the gases or vapors into a smaller spaceand forcing the said gases or apors through the o ening or hole C (Fi s.1 and 8) into the tube G, which tube G (Figs. 1, 2, 3 and 5) is securelyattached or fastened to the compression ring K in a suit ble isubstantial and durable manner. and thus works in the same direction andat the same rate of speed as the compression ring C.

As the tube G which I have named the gas conveyor and shall all it suchhereafter, descends or moves forward in the tubular chamber Z (Fig. 1)the compressed gases or vapors are forced out of the compression chamberB through the opening (1" into the gas conveyer G and the tubularchamber Z; when the compression ring K has nearly reached the end of thedownward or power stroke, the gas conveyor G being attached to thecompression ring K, will be drawn down the same distance and begin touncover the port D in the. explosion chamber and when the power strokeis completed, the top of the gas conveyer G will be on a level with oropposite to the bottom or lower side of port D (Fig. 1). thus uncoveringthe port D completely, allowing the compressed gases or vapors to escapefreely into the power or explosion chamber E (Fig. 1). At the same timethe exhaust port F is opened or uncovered by the piston head H allowingthe burnt or exploded gases to escape (Fig. 1). As the piston head Hascends or makes the backward stroke, the gases or vapors that haveentered the power or explosion chamber E through the port D are againcompressed by the receding action of the piston head H for the nextexplosion in the power chamber E (Fig. 5) the.port D is then covered orclosed by the gas conveyor G rising or going backward in the tubularchamber Z, reaching the top, or near the top. of the chamber Z (Fig. 5)when the explosion occurs in the power chamber E, thus closing orcovering the port D completely and preventing any loss of power ordanger of the exploding gases or vapors from entering the compressionchamber B, through the gas conveyer G. Attention is also called to thefact that the exhaust port F is closed at this time by the piston head H(Fig. 5).

The sleeve Q containing the diagonal slots and bars at the port D (Figs.1 and 4) is for the purpose of keeping the expanding rings R on the gasconveyer G from coming out in the port D which surrounds the gasconveyer G. (This however may alsobe accomplished by casting thesediagonal bars in port D.) The idea and purpose remains the sameregardless of the manner in which these slots and bars are made to occuraround the port D. The port D surrounds the gas convever G in the mannershown in Figs. 1, 4 and 5 so that when the explosion takes place in thepower or explosion chamber F. the

ressure that backs into the port D will lie equal all around the gasconveyer G and thus prevent unequal wearing. llaving this port D formedor made in the manner shown in Figs. 1 and *lalso allows freer admissionof the gases or vapors into the explosion chamber E when the gasconveyer G has uncovered the port D a- The strainer L (Fig. 1) may beused or left out altogether, or a strainer of another design may beused. The strainer L is tubular in form and perforated, having gauzewire screen fastened in its base or lower extremity so that the screenmay be taken out and cleaned. The strainer L has a flange at its upperor backward extremity which is broad enough to be caught and held inplace by the cap M. The strainer L should be long enough to extend downinto the hollow gas conveyer G when the power stroke is complete, "so asto prevent the strainer from working on of place (Fig. 1).

The cap M shown in Figs. 1 and 5 closes the top of the tubular chamber Zand prevents the escape of the gases or vapors in that direction: italso holds the sleeve Q and the strainer L in place.

\Vherever the letter R appears in the Figs. 1, 2 and 5 it indicatesexpanding rings, and as these rings are all of similar construction, andused for the same purpose, that is, to prevent the escape of gases, itwas not considered necessary to use a different letter or set of lettersto indicate each ring.

Letter S shown in Figs. 1 and 5 indicates grooves cut in the base of thecompression sleeve I for the purpose of carrying some of the splashedoil into the cylinder T in order to lubricate these parts.

Letter J shown in Figs. 1, 2 and 5 indicates ports or openings cutthrough the base of the piston head H above the compression ring K forthe purpose of preventing compression above the compression ring K byallowing the air to work in and out of the chamber formed above thecompression ring K (Fig. 1). The openings J will also admit some of thesplashed oil into the said chamber and help to lubricate in this manner.Compression may also be prevented in the chamber above the compressionring K in another manner, by leaving an opening in a suitable part ofthe top of the cylinder V, this however I consideran inferior method asit allows dust and dirt to be drawn into the cylinder I from theoutsideand does not allow of any chance for lubrication from the splashed oil.

'The letter P shown on the top of the cap M Figs. 1 and 5 indicates thelocation of a reliefror safety cock or valve.

The letters Pl. shows the location of a combination spark plug, reliefor safety cook or valve and priming cup. (Figs. 1 and 5.) The spark plugmay however be placed in this location, and a relief or safety cook orval vc and priming cup, at any other suitable point at or near the topof the explosion chamber E, or the spark plug may be placed at any othersuitable point.

Letter N in Figs. 1, 2, 3, and 5 is the piston pin which fastens theconnecting rod 0 (Figs. 1, 2, 3 and 5) to the piston head H.

The letter W indicates the water jacket (Figs. 1, 4, and 5).

The gas conveyer G may be designed 0G at the side and near the top ofthe gas conveyer G which port is covered with perforated material L, andthrough the port D into the explosion chamber E. If this method is usedvents or openings VT would have to be left in the top of the tubularchamber Z to prevent air compression here, as the closed top gasconveyer G works up and down and would also be supplied with a safetyvalve ()L to provide an exhaust in case the gas should explode beforereaching the cylinder or expansion chamben This design is mentioned inorder to cover my invention more completely. The

- openings HH in the top' of the compression chamber are to allow thecompression ring to be raised without any compression. at its upper end.

All castings, forgings and parts mentioned and described in thesespecifications, are to be made proportional to attain the ends desired.

1 am aware that there are motors that use crank case compressiondirectly, but these differ widely from my invention in the manner ofconfining the gases or vapors while they are being primarily compressed,also in conveying the said gases or vapors into the power or explosionchamber. There is also a motor that uses a compression chamber, but itis vastly different from my invention, in its action, construction,manner of confining the compressing gases or vapors, and system ofdelivering these gases or vapors into the power or explosion chamber.This motor differs from mine by making the primary compression on theupward or backward stroke of the piston, and forcing the said gases orvapors through a tube or cylinder into the explosion or power chamber ofa separate and distinct unit. My invention makes the primary compressionon the downward or power stroke of the piston. and by my system thegases or vapors are conveyed or forced into the explosion or powerchamber of the same unit. where a further compression takes place or thebackward or receding stroke of the piston head, thereby making itpossible to have will a perfect, practicable, and simple, single unitmotor, complete in itself.

By direct double compression I mean thatv with-my invention the gases orvapors are primarily compressed by the explosion or power stroke of thepiston, by the compression ring in the compression chamber, beforedescribed, and that the said compressed gases or vapors, after beingthus com pressed, are forced or conveyed into the explosion or powerchamber through a port or opening in the side of said chamber at or nearits upper extremity, where the gases or vapors are again compressed bythe receding action of the piston, before explosion. The compressedgases or vapors, however may be admitted into the explosion chamberthrough a port or opening in the side of said chamber at or near thebottom of said chamber and still use my system of compressing andconveying the gases or vapors. If this system is used it will benecessary to have a. small deflector DF on the top or end of the pistonhead, to prevent the fresh charge from the passageway GG from blowingstraight through and out of the exhaust. The compressed gases or vaporshowever may also be conveyed and admitted into the explosion or powerchamber through a port or opening AG. in the side of said chamber at ornear the bottom of said chamber, after the gases or vapors are drawn inand compressed by my design of compression chamber, and without using mysystem of conveying, but by using the tube or gas passageway in Fig.'10connected from the port or opening CS in the lower part of thecompression chamber V to the port or opening AG in the side of theexplosion chamber a at or near the bottom of said explosion chamber. Theexplosion chamber E and the cylinder I may also be of the samediameteras shown in Fig. 9. The letters AG in Fig. 9 indicate thestrainer to prevent popping back. I

WVhat I claim as my invention and desire to secure by Letters Patentis 1. An internal combustion engine having an explosion chamber, apiston Within the same, a crank case and compression chamber below saidexplosion chamber and of greater diameter than the same, a compressionring connected to said piston for compressing explosive mixture in thesaid compression chamber, means connected to said compression ring forpreventing the escape of the compressed gas into the crank case, andmeans connected-with said compression ring for conveying said compressedgas to said explosion chamber.

2, An internal combustion engine having an explosion chamber, a pistonwithin the same, a compression chamber below said explosion chamber,means connected to said piston for compressing explosive mixtures insaid compression chamber, a passageway communicating with said explosionchamber and said compression chamber, a traveling conveyer attached tosaid means for regulating the admission of explosive mixture from sa1dpassageway to said explosion chamber.

3. An internal combustion engine having an explosion chamber, a pistonwithin the same, a compression chamber below said explosion chamber,compressing means connected to said piston for compressing explosivemixtures in said compression chamber, a passageway communicating withsaid explosion chamber and said compression chamber, and a tubeconnected t9 saidcompressing means operating in sa1d passageway forregulating the admission of explosive mixture to said explosion chamber.

4. An internal combustion engine having an explosion chamber, a pistonwithin the same, a compression chamber below said explosion chamber andof greater diameter than the same, compressing means connected to saidpiston for compressing explosive mixtures in said compression chamber,means connected to said compression means for preventing the escape ofthe compressed gas into the crank case, a passageway communieating withsaid explosion chamber and said compression chamber, means connected tosaid compressing means operating in said passageway for regulating theadmission of explosive mixture to said explosion chamber, and means forpreventing the popping back of the flame from said explosion chamber,

5. An internal combustion engine having an explosion chamber, a pistonwithin the same, a compression chamber below said explosion chamber,compressing means connected to said piston for compressing explosivemixtures in said compression chamber, a passageway communicating withsaid explosion chamber and said compression chamber, atube connected tosaid compress1on means operatlng 1n sa1d passageway for regulating theadmlssion of explosive mixture to said explosion chamber, and means forpreventingthe popping back of flame from said explosion chamber.

6. An internal combustion engine having an explosion chamber, a pistonwithin the same, a .compression chamber below the said explosion chamberand of greater diameter than the same, compressing means connected tosaid piston for compressing, explosive mixtures in said compressionchamber, means connected to said compressing means for preventing theescape of the compressed gas into the crank case, a passagewaycommunicating with said explosion chamber and said compression chamber,means connected to said compression means operating in said passagewayfor regulating the admission of explosive mixtures to said explosionchain- 7. An internal combustion engine having an explosion chamber, aplston Within the same, a compression chamber below said ex-' plosionchamber, compressing means connected to said piston" for compressingexplosive mixtures in said compression chamber, a passagewaycommunicating with said explosion chamber and said compression chamber,a tube connected to said compression means andoperating in said passage-Way for regulating the admission of explosive mixture to said explosionchamber, and screen means for preventing the popping back of flame from.said explosion chamber.

8. An internal combustion engine having an explosion chamber, apistongwithin the same, a crank case, a compression chamber below saidexplosion chamber and of greater diameter than the same, a'compressionring connected to said piston for compressing ex- I plosive mixtures insaid compression chamber, means cooperating with sald compression ringfor preventing the escape of compressed mixture into said crank case,and means connected with said com ression ring for conveying saidcompresse mixture to said explosion chamber.

9. An internal combustion engine having an explosion chamber, a pistonwithin the same, a crank case, a compression chamber below saidexplosion chamber and of greater diameter than the same, acompressionring connected to said piston for compressing explosivemixtures in said compression chamber, a sleeve cooperating with saidcompression ring for preventing the escape of compressed mixture intosaid crank case, and means connected withv said compression ring forconveying said compressed mixture to said explosion chamber KLE- DUNE.Witnesses:

JOHN E. MCCALMONT, ROY (Dwain

